Limit-stop brake apparatus.



A. SUNDH. LIMIT STOP BRAKE APPARATUS. APPLICATION FILED AUG. 16, 1907.

926,620. Patented June 29, 1909.

wane we 0 46 avwe'n foz springs 17 re-acting between t magnet frame 13 and shoulders 18 formed on AUGUST SUNDH, OF YONKERS, NEW YORK,

JERSEY CITY,,NEW JERSEY,

ASSIGNOR TO OTIS ELEVATOR A CORPORATION COMPANY, OF OF NEW JERSEY.

LIMIT-STOP BRAKE APPARATUS.

Specification of Letters Patent.

Patented June 29, 1909.

Application filed August 16, 1907. Serial No. 388,813.

To all whom it may concern:

zen of the United States, residing in Yonkers,

in the county of Westchestcr and State of New York, have invented a new and useful Improvement in Limit-Ste Brake Apparatus, of which the following 18 a specification.

My invention relates to safety appliances forelevators, and has for an object the rovision of means for quickly and powerf iilly applying the brakes in an elevator system when the car is carried beyond its'normal limit of travel in either direction.

A further object of the invention is to provide means for applying the brakes when the car is carried beyond its normal limits of travel, with a power varying with the momentum of the car, so that the faster the car is traveling when it reaches its normal limit and the greater the load, the more quickly and powerfully will the brakes be ap lied. Other objects will appear more ful y herematter, and the scope of the invention will appear from the appended claims in which thenovel combinations of elements and their arrangements are speciiied.

The accompanying drawing is a diagrammatic view of a traction elevator system in combination with which my invention is used, and shows in detail the safety appliances.

The elevator car C and the counterweight W are connected by a rope or cable 1 assing over the overhead sheaves 2, 3, 4 an 5 and frictionally engaging the drive sheave 6 secured to the shaft 7 of a motor M1 brake shoes 8 are pivoted to the lower ends of the brake levers 9 and 10 whichare fulcrumed on plvots 11 and 12, respectively, carried by the motor frame or other suitable support. \Vhen the upper ends of the brake levers 9 and 10 are moved outward, the brake shoes 8 are applied to the drive sheave 6, and when the upper ends of the levers are move inwardly the brake shoes are released. The brakes are controlled by an electro-magnet which comprises an iron frame 13, a solenoi or winding 14, and two cores or armatures 15 which are connected by ivots 16 to the brake levers 9 and 10. Will denergized the brakes are a plied .by 0011 lie ends of the the cores 15. Then a current is passed through the winding 14 the cones 15 are The en the magnet is drawn inward against the tension of the springs 17, moving the brake levers about their fulcrums 11 and 12, and releasing the brake shoes from the driving sheave.

Current is supplied to the brake magnet from any suitable source of current supply, the positive and negative leads of whic 1 are designated and respectively. manually operable controlling switch 19 in the brake magnet circuit may be located in the car or at any other position from which the elevator ear is to be controlled. An automatic switch 20 is also placed in the brake magnet circuit. This switch comprises a fixed contact 21, carried by but insulated from an arm 22 secured to or forming an integral extension of the brake lever 10, and a movable contact 23 carried by and insulated from the switch lever 24, pivoted at 25 to a lug on the brake lever 10. A coil spring 26 between the lower end of the switch lever 24 and the brake lever 10 holds the switch normally closed with the contacts 21 and 23 in engagement. 4

Above the brake magnet is a dash-pot comprising a cylinder 27 which may be formed integral with the magnet frame 13 as shown. The dash-pot has two pistons 28 and 29 provided with piston rods 30 and .31, respectively. The piston rod 30 1s ivoted at 32 to the upper end of the brake ever 9. Pivoted to the brake lever 10 in line with the piston rod 31 is a short arm 33. A coil spring .34 surrounds the adjacent ends of the piston rod 31 and the arm 33 and is secured to said parts, normally holding them a short distance a art. An arm 35 carried by the iston r0 31 normally extends within a short distance of the switch lever 24. Mounted on the dash-potw is a valve 36 which is adjustable to restrict to any desired degree an air passage leading into the cylinder between the pistons.

At the bottom of the path of the car and counterweight, res ectively, are two sprin buffers 0r cushions I; These buffers are i entical in construcone of them being shown in section on comprises a base 37 in the form of a hollow cylinder provided with an air chamber '38. A- cylindrical rod or iston 39 fits closely in the chamber 38 and is movable u and down therein. Each rod 39 has a bee 40 carrying a block 41 of ruletion, the drawing. Each her or other suitable material in the path of the elevator well and in the switch 19 is closed.

main.

A the outside of the from the positive the car or counterweight. A coil spring 42 surrounds the rod 39 and base 37 with its ends abutting against the head 40 and a flange 43 formed on the base 37. The spring normally holds the rod 39 in its upper position in which the rod only extends part way into the base. Located between the two bases 37 is a valve chamber 44 in which are two valves 45 which in their closed positions abut against stops 46, but are freely movable in the opposite direction. Between each end ofthe valve chamber 45 and its adj acent cylinder 37 is an air duct 47 communicating with the valve chamber and theair chamber 38. An air pipe 48 leads from the center of the valve chamber 44 to an air duct 49 communicating with the center of the (lash-pot cylinder 27.

he operation of the device is as follows. When the elevator car is brou ht to rest the parts assume the positions s own by the drawing. The brake magnet circuit is open at the switch 19, the magnet is denergized and the brakes are held to the drive sheave by the s rings 17 acting through the brake levers. 1 f now it is .desiredto start the car, Y This closes a circuit through the brake magnet coil as ollows,

main, through the wire 50, magnet coil 14, wire 51, contacts 23, 21, wire 52, switch 19, and wire 53 to the negative The coil 14 being thus energized, the cores 15 are pulied inward against the pressure of the springs 15 and release the brakes. The switch 19 of the brake magnet circuit may be connected to and operated by the controller for the motor M in a manner well known-in the art, so that the brake is releasedand the motor started by a single operation of the controller lever.

When it is desired to stop the car the current is cut off from the motor and the switch 19 vis opened. This denergizes the brake magnet and allows the springs 17 to force the bra e levers 9 and 10 outward and powerfully apply the brakes. The dash-pot at this time acts to retard the application of the brakes, as the outward movement of the brake levers carrying with themthepistons 28 will produce a partial vacuum between the pistons, and the atmospheric pressure on istons will oppose the movement of the brake levers. The restricted air passage controlled by the valve 36 will now admit air slowly into the cylinder, allowing. the pistons to move outward gradually and ap ly the brakes gradually and smoothly. T of a size tocompletely control the speed with which the brakes are ap lied, and by its use the sudden or jerky app ication of the brakes, with the consequent slipping and wearing of the cables, annoyance to passengers, and other objectionable features, is

avoided. I do not claim, however, as my e dash-pot may be made l f I i l l i invention the idea broadly of 'usin a dashpot as a retarding device for the bra (es.

If the operator has failed to a ply the brakes, or for any other reason tlib car is moving rapidly as it approaches its limit of travel in either direction, the brakes will automatically be set quickly andpowerfully. f the car is moving downward, for example, it will strike the block 41, moving it downward, compressing the spring 42 and compressing the air in the chamber 38. Both the compressed air in the chamber 38 wi l re act as a cushion to prevent a sudden stopping of the car. At the se me time the compressed air in the chamber 38 will expand through the air passage 47, valve 45, pipe 48 and air duct 49 into the dash-pot cylinder 27. This air in the cylinder 29 will force the pistons outward to apply the brakes.

When the piston 29 begins to move outward, the coil spring 34 is compressed until the end of the piston rod 31 engages the end of the rod 33. As soon as this compression of the spring commences, the arm 35 carried -moving it about its the switch lever 24, pivot 25 and separating the switch contacts 21, 23. This opens the brake magnet circuit and allows the brake to be applied under the combined action of the brake springs 17 and the compressed air in the dash-pot. It will thus be seen that when this automatic device operates the brakes are applied much more quickly and by the piston rod strikes operated in the usual way, for not only is the retarding action of the dash-pot entirely removed, but it is replaced by the compressed air which augments the speed with which the brakes are applied and the power with which 105 they are held. It will also be observed that the speed and power with which the brakes are applied wil vary with the speed of the car or counterweight when the bufler B is moving rapidly more 110 e 48 and into either Although I have shown and described a 120 practical embodiment of my invention, I do not wish to be limited to the exact construction disclosed, as various changes in details of construction and arrangement of parts might be made without spirit of the invention.

What I claim as new and desire to secure by Letters Patent of the United States is:-

held on with more power than when they'are the dash-pot cylinder departing from th 1. In an elevator, the combination witha motor, a car, drivlng connectlonsbetween 139 re -u motor, a car,

, to the power with which the brake is applied.

' means to a ply 25 and means automatically opera 3. In an elevator, the combination with a car, a motor, driving connections between the car and motor, and a' brake, of a dash-pot connected to the brake and normally retarding its application, and means toovercome such retardation-and add to the power with which the brake is applied.

4. In a traction elevator, the combination with a car, a driving sheave, a cable connecting the car and driving sheave, a brake, and

the brake, of a dash-pot connected to t e brake and normally retarding its application, a manually operable device for controlling the brake-appl ing means, termined points in the travel of the car-for applyin the brake, overcoming its retardation an adding to the power with which it is applied.

5. In an elevator, the combination with a motor, a car, driving connections between the motor and car, an electro-magnetic brake, and a manually operable device for controlling the brake magnet circuit, of a ing its application, and

dash-pot connected to the brake and normally o erative to retard the application of the bra e, and means automatically operative at predetermined points in the travel of the car to control the brake magnet circuit and operate the dash-pot as an accelerating device in applying the brake.

6. The combination with a brake and means'for'ap lying the brake, of a device connected to lie'brake and normally retard means for converting said retarding device into an accelerating device.

7. The combination with: a brake and means for applying the brake, of a dash-pot connected to the brake and normally operative to retard its application, and means for operating the dash-pot as a motor to acceler ate the application of the brake.

8. The combination with a brake lever, a brake shoe carried thereby, and means for moving the levenin a direction to apply the brake shoe, of an air cylinder, a piston connected to the brake lever and movable in the cylinder a ainst an unbalanced air pressure to normal y retard the a plication of the brake, and means to 'prod iice a preponderance of air pressure on the piston 111 a direcle at prede tion to accelerate the application of the brake. v

' 9. The combination'with a brake lever, a brake shoe carried thereby, and means for moving the lever in a direction to apply the brake shoe, of an air cylinder, a piston in the cylinder, a connection and brake lever for moving the piston in a direction to reduce the air pressure in the c12 1- inder and retard the application of the bra e and means for introducing air into the cyhn-' der above atmospheric pressure to accelerate the ap lication of the brake. I

10. 11 an elevator, the combination with a motor, a car, driving connections between the motor and the car, a brake, and means for applying the brake, of an air cylinder, a piston in the cylinder, connections between the piston and brake for moving the piston outwardly against atmospheric pressure and roducing a artial vacuum in the cylinder in the norma ap lication of the brake, and means for intro uoing compressed air into the cylinder to accelerate the application of the brake. g

11. In an elevator, the combination with a motor, a car, driving connections between the motor and the car, a brake, and means for appl ing the brake, of an air cylinder, a piston t erein, connections between the piston and brake for moving the iston outwardly as the brake is being ap ied, manually operable means for contro ling the ap plication of the brake, an air chamber beneath the car, means engaged by saidcarasit a proaches its limit of travel for compressing tiie air in said chamber, an air passage from said chamber to the interior of the cylinder, and means operated by the compression of the air for automatically controlling the application of the brake.

12. In an elevator, the combination with a motor, a car, driving connections between the motor and car, i an eIectro-magnetic brake, and a manually operable device for controlling the brake magnet circuit, of a dash pot connected to the brake and operable to normally retard its ap lication by produciniafpartial vacuum in t e dash-pot, a spring u er in the path of travel of the car, means operated by said buffer for introducing compressed air into the dash- 0t, and means operated by the compresse air for automatically controlling the rake magnet circuit.

13 In an elevator, the combination with a motor, a car, driving connections between the'motor and car, a brake, and means for applying the brake, of a dash-pot connected to the brake and normally operable to retard its application, s ring bufier mechanism in the path of trave of the car and comprising an air chamber, means for compressing the air in said chamber, anair passage leading from said chamber to the dash-pot cylinder,

between the piston automatically contro the brake when the circuit the motor and to admit compressed air to the'cylinder, and means operated by the compressed air'for automatically the brake. N

14. In an elevator, the combination with a motor, a car, operative connections between car, a brake, and means for applying the brake, of a dash-pot connected to and normally retarding the ap lication of the brake by the production o a partial vacuum in the dash-pot, a spring buffer in the path of travel of the car and comprising an air cylinder, a piston operatedby the car for compressing air in the cylinder, an air passage leading from the cylinder to the dashpot, a valve in the air 'assage and means for llihgthe application of the brake. 15. In a traction elevator, the combination with a drive sheave, a car, a counterweight, a cable connecting the car and counterweight and frictionally engaging the drive sheave, a brake'and means for applying the brake, of a dash-pot operatively onnected to the brake, spring buffers in the path of movement of the car and counterweight respectively and comprising. air cylinders, means for compressing the air in the respective cylinders as the car or counterweight exceeds its normal limit of travel, a valve passa es communicating with the valve cham er and the respectlve'cylinders, an air passage extending from the valve-chamber to the dasht, and valves in said chamber between sai last-named air passage and the air passages communicating with the cylinders. 16. In an elevator, the combination with a motor, .a car, driving connections between the motor and car, an ele'ctro-magnetic brake operative to release the brake when the brake magnet circuit is closed, means for applying is open, and a manual switch in the circuit, of an air cylinder, a piston in the cylinder, connections between the piston and the brake for moving the piston in a direction ressure in the cylinder when the brake is eing controlled manually, means for automatically forcing air into the cylinder at predetermined periods in the travel of the car, an automatic switch in the brake magnet circuit, and means for opening said switch whenair is forced into said cylinder.

17. In a brake mechanism, the combina- .tion witha brake shoe, a brake lever and an electro-magnet operatively connected to the controlling the application of said switch when t I In a traction elevator, the combinachamber, air

to reduce the air lever, of an air cylinder, der, a coil spring between the piston. and brake lever, a switch in the circuit of the electromagnet,"means for forcingair into the cylinder and operating the piston to compress the coil spring], and means for operatlng e spring is compressed.

18. tion with a car, a counterweight, a drive sheave, a cable connected to the car andcounterweight and en aging the drive sheave, brake levers, -brake sioes carried by the levers in position to engage I brake springs, an electro-magnetconnected to said levers and operative to release the brakes when the magnet is energized, and a manually operable switch in the magnet cir-. cuit, of an air 'cylinder located between the brake levers, pistons in the cylinder, piston rods on the plstons, one of said rods being a piston in the cylinthe drive sheave,

pivoted to a brake lever-and movable out I wardly therewith when the brake is applied, a coil spring connection between the other piston rod and the other brake lever, electrlcal contacts in the brake magnet circuit,

one of said contacts being carried by said last-named lever, a switch lever the brake lever and carrying the'other contact, means forinormally holding the con tacts in engagement, an arm carried by saidlast-named piston rod and extending 111130,

AUGUST SUNDH. U

l Witnesses:

CHAs. M. NISSEN, ALFRED 0. BEcHnr.

mechanism for applying the same, a fluid motor for assisting said applypivoted to 

